As discussed in UK Patent No. 2149650, with certain products, particularly meat, it is difficult to keep the size of cut portions constant. This is particularly the case when dealing with a product such as pork chops.
The earlier patent describes apparatus for cutting or sawing a product such as a side of pork into uniformly sized portions which includes means for determining the area of the end face of a region of the product from which pieces are to be cut or sawn, computing means having stored therein a numerical density value for the material to be cut and a numerical weight value corresponding to the desired weight per cut piece, the computing means being adapted to compute from the measured area of the end face, the depth of the cut required to obtain a piece of the desired weight. Means is provided for adjusting the depth of cut using the computed thickness value to obtain pieces of the desired weight and there is further means enabling correction of the numerical density value in the computing means by sampling the weight of a cut piece.
The apparatus described in the aforementioned patent specification includes a closed track around which a meat carrying platform moves with a piece of meat on the platform. A bandsaw cutter is located at one position around the track operating vertically and a guide deflects the cut slice onto a check weighing apparatus from where the checked pieces can be loaded into a bin or onto a conveyor. The movement of the platform around the track is controlled by a drive unit which itself is controlled from a control centre and the position of the bandsaw relative to the end face of the meat is also controlled by another drive unit which is computer controlled.
At a position remote from the bandsaw is located and X Y scanning device for producing an area signal corresponding to the area of the piece of meat which is next to be cut by the bandsaw.
Whilst such apparatus can be made to function at moderate speeds, high speed operation is limited due to the considerable spacing between the scanner and the bandsaw. Although it is possible to utilise the delay between the scanner and the bandsaw for the purpose of computing the depth to which the piece is to be cut, with even low speed computing techniques, the time period is excessive and the throughput of the machine is therefore considerably limited.
It is one object of the invention to provide a machine which whilst cutting to the same degree of accuracy will nevertheless allow a greater throughput of cut product.
It is a further object of the invention to apply the sizing technique described in the aforementioned patent No. 2149650 to a bandsaw in which the cutting is effected in a horizontal plane rather than a vertical plane.
It is a further object of the invention to provide a machine for cutting constant volume pieces of a product.
It is a further object of the invention to provide a sizing and cutting apparatus for removing constant volume pieces of product by a horizontally acting bandsaw in which the thickness of the material to be removed by the bandsaw is adjustable at high speed in response to an electrical signal relating to the area of the product concerned so as to enable variations in thickness of cut to be made "on the fly", to follow changes in cross-sectional size and shape of the product as pieces are removed therefrom, to enable pieces of constant volume to be delivered at the output of the machine.